Snap action relay



July 3, 1956 J w. MCCLAIN 2,753,416

SNAP ACTION RELAY Filed May 5, 1953 ISLE-=3 26 I7 I l9 M2! 4 I INVENTOR. JOSEPHW. McCL-AIN United States Patent SNAP AcTIoN RELAY Joseph W. McClain, Logansport, Ind., assignor to Essex Wire Corporation Application May 5, 1953, Serial No. 353,145

1 Claim. (Cl. 200-87) My present invention relates to improvements in snap acting electromagnetic relays. A principal object of this invention is to provide a relay with improved snap acting means for operating electrical contacts. Another object is to provide an improved snap-acting relay of compact size with increased sensitivity and life expectancy.

Other advantages of the invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification.

In the drawings:

Fig. 1 illustrates the connection of the relay in a motor circuit.

Fig. 2 is a side elevation of the relay in normal position.

Fig. 3 is a side elevation of the relay in the energized position.

Fig. 4 is a plan view.

The operation of the relay can be best understood by reference to Fig. 2. The relay coil is represented at 14 and when energized upon application of sufiicient voltage it attracts the armature or clapper 15. The armature is shown in the attracted position in Fig. 3. On attraction of the armature 15 by the coil, the armature abuts against the split core 17 positioned in the relay coil. The core 17 is split to accommodate a shading washer 16. For D. C. operation of the coil 14, the core 17 need not be split and the shading washer 16 may be omitted, as is Well recognized in the art.

The armature 15 passes through and is pivotally mounted in the bracket 18. The coil spring 19 is attached near the end of the armature 15 remote from the end attracted by the coil 14 and exerts a normally downward pull so that the end remote therefrom is normally biased away from the coil.

The armature 15 has an integral tongue 23 extending outwardly from the body of the armature and then horizontally so that a part of the tongue toward the free end thereof is parallel to the body of the armature. The free end of the tongue 23 is grooved to receive one end of the spring 24 which provides the snap action in opening and closing the contacts. The other end of the spring 24 is engaged with the spring 25. The spring 25 is fixed at one end to the bracket 18 and the other end carries the movable contact 22. The spring 25 has a blanked out center portion 32 through which the tongue 23 protrudes. The edge 33 of the blanked out portion adjacent the movable contact serves to receive the other end of the spring 24 remote from the tongue 23. The spring 24 is longer than the straight line distance from the grooved end of the tongue 23 to the edge 33 of the spring 25 with the result that it must be sprung into position. The end of the spring 24 in contact with the tongue 23 is bent slightly so that the best portion is in the plane of the tongue 23. Proceeding toward the opposite end and at a point near the end the spring is bent through substantially and then bent sharply in the opposite direction to form a V-slot. This slot engages the edge 33 of the spring 25.

As aforesaid the spring 24 provides for the snap action in opening and closing the contacts. This snap action is induced by the pivotal movement of the armature 15 as dictated by the coil 14. When the coil is non-energized, the armature is in the normally open position and the contacts 22 and 26 are in the normally closed position shown in Fig. 2. Upon energization of the coil 14, the contacts are opened as in Fig. 3. Attraction, and release of the armature 15 by the coil 14 causes pivotal movement of the armature due to its support by the bracket 18. Pivotal movement of the armature in turn causes the spring carrying tongue 23 to move in and out of the blanked out portion of the spring 25 and in effect to move from one side of the spring 25 to the other. In the deenergized position of Fig. 2, tongue 23 is above spring 25 and spring 24 exerts a downward line of force on the contact 22 holding the contacts 22 and 26 in the closed position. On attraction of armature 15 to core 17, the tongue 23 moves to the lower side of spring 25 compressing spring 24 until it buckles and snaps through the blanked out portion of the spring 25. In buckling, the spring 25 exerts an upward line of force on the contact 22 causing this contact to separate from the fixed contact 26 with a snap action.

The stops 30 and 31 are provided merely to restrict the movement of the armature 15 and the movable contact 22. Although only the preferred embodiment of the invention is described, it is to be understood that the invention may have other forms falling Within the scope of the claim which follows.

I claim:

In a relay, a coil, an armature attracted by said coil, means normally biasing said armature away from said coil, a tongue extending from said armature, said tongue containing a spring receiving groove at the free end thereof, a movable contact, a fixed contact, a spring fixed at one end and carrying said moveable contact at the remote free end thereof for contacting engagement with said fixed contact, said spring also containing a blanked out center portion adapted to permit the passage of said tongue, a second spring constrained between said tongue and the peripheral edge of said blanked out portion one end of said second spring adapted for hearing engagement in said tongue groove and the opposite end of said second spring formed into a V-shape for hearing engagement with said first mentioned spring whereby movement of said armature causes said second mentioned spring to buckle from one stable position to another stable position thereby moving said first mentioned spring to make and break said contacts in a snap acting manner.

References Cited in the file of this patent UNITED STATES PATENTS 2,068,374 Carlson Jan. 19, 1937 2,170,748 Eaton Aug. 22, 1939 2,321,834 Marco et al June 15, 1943 2,374,986 Fetter May 1, 1945 2,525,044 Puerner Oct. 10, 1950 2,558,219 Kohl June 26, 1951 FOREIGN PATENTS 551,021 Great Britain Feb. 4, 1943 

